/// <summary>
/// Returns the count within a range.
/// </summary>
/// <returns></returns>
public int CountInRange(
Bound <TK> start,
Bound <TK> end)
{
var tailIndex = GetTailIndex(end);
if (tailIndex != -1)
{
if (tailIndex >= _itemList.Count)
{
tailIndex = _itemList.Count - 1;
}
while (tailIndex >= 0 && !BoundExtensions.IsLessThan(end, _itemList[tailIndex].Key, _itemComparer.KeyComparer))
{
tailIndex--;
}
if (tailIndex == -1)
{
return(0);
}
var headIndex = AdvanceIntoRange(GetHeadIndex(start), start);
return(Math.Max(tailIndex - headIndex + 1, 0));
}
return(0);
}
public IEnumerable <KeyValuePair <TK, TV> > EnumerateRange(
Bound <TK> start,
Bound <TK> end)
{
var headIndex = AdvanceIntoRange(GetHeadIndex(start), start);
for (var ii = headIndex; ii < _itemList.Count && BoundExtensions.IsLessThan(end, _itemList[ii].Key, _itemComparer.KeyComparer); ii++)
{
yield return(_itemList[ii]);
}
}
/// <summary>
/// Advances a head index until it reaches a valid point in the range.
/// </summary>
/// <param name="headIndex"></param>
/// <param name="start"></param>
/// <returns></returns>
private int AdvanceIntoRange(
int headIndex,
Bound <TK> start)
{
if (headIndex == -1)
{
headIndex = 0;
}
while (headIndex < _itemList.Count && !BoundExtensions.IsGreaterThan(start, _itemList[headIndex].Key, _itemComparer.KeyComparer))
{
headIndex++;
}
return(headIndex);
}
